1. Field of the Invention
The invention relates to a circuit configuration having single-electron components and which is suitable, inter alia, for use as a logic circuit.
Present-day integrated circuit configurations for logic applications generally use CMOS technology. As components progressively become smaller, conventional CMOS technology is reaching its limits.
With regard to further miniaturization, so-called single-electron components have been proposed. There, switching processes are carried out using individual electrons. An investigation into such single-electron components is known, for example, from Rosner, et al., Microelectronic Engineering, Volume 27, 1995, pages 55-58. Single-electron components are tunnel elements which are connected to adjacent connections via tunneling contacts. Charge movements through these tunneling contacts take place both by means of the quantum-mechanics tunnel effect and simply by thermally overcoming a potential barrier, in which these charge movements occur sufficiently rarely. The tunnel elements are, for example, in the form of small conductive islands, which are surrounded by an insulating structure. If a voltage U which satisfies the conditions for Coulomb blockade is applied to the two connections, that is to say whose magnitude is .vertline.U.vertline.&lt;e/(2C), then the charge of the tunnel element cannot change, owing to the potential conditions, as long as the following is true for the thermal energy ##EQU1##
Here, k is the Stefan-Boltzmann constant, T is the temperature, e is the electron charge, and C is the capacitance of the tunnel element.
If a greater voltage is applied, electrons can flow via one of the tunneling contacts to the tunnel element. These single-electron components are operated such that individual electrons move in each case.
By actuating the tunnel element via a gate electrode which capacitively influences the tunnel element without any tunnel movements occurring in the operating voltage range, it is possible to overcome the Coulomb trap or blockade. If the electrical charge acting at the gate electrode is suitable, the single-electron component has an approximately linear current/voltage characteristic, passing through the origin. Such a gate-controlled single-electron component is referred to as a single-electron transistor in the pertinent literature.